A Gentle Introduction to Resampling Techniques

2 Overview of resampling 2 Permutation Methods 3 Bootstrapping 3 Monte Carlo 4 Failure of t-test: Girl Scout cookie sales 4 Demonstration of permutations 5 Demonstration of Howell‟s resampling programs 5 Howell‟s example: Hurry up, Fella! 5 parametric t 6 Permutation tests (also called Randomization tests) 6 t as a measure of an effect 6 Howell‟s Resampling program 7 Howell‟s Randomization (permutation) procedure with t as an effect measure 8 Howell‟s difference between medians as an effect measure 9 Impact of outliers 9 parametric t-test 9 permutation test using t-value 11 permutation test using difference between medians 12 Entering our own data into Howell‟s program 12 create your .DAT text file data set 12 Randomization (permutation) test difference between medians 14 Randomization (permutation) test using t as a measure of group difference 15 Bootstrapping demonstration 15 difference between medians – Girl Scout cookie example 17 bootstrapping difference between medians – Parking Lot data 18 Resampling with correlations 19 randomization (permutation) tests for correlation 20 bootstrapping correlations 21 Bootstrapping regression weights with an SPSS macro 22 References for resampling